advances in the diagnosis and management of ... - perinatalgreen dots divided by turquoise plus...

Advances in the

diagnosis and

management of

neonatal

thrombocytopenia

Robert D. Christensen, MD April 13, 2013

19th INTERNATIONAL SYMPOSIUM ON NEONATOLOGY

Outline 1) Reference ranges for platelet

counts

2) Advances in understanding congenital hyporegenerative thrombocytopenias

3) Is it time for a new platelet transfusion paradigm?

4)Romiplostim and Eltrombopag

Outline 1) Reference ranges for platelet

counts.




Platelet “Reference Range”

for Neonates

• >47,000 neonates from

Intermountain Healthcare, Utah,

USA

• All run on the same model of

platelet counter (Beckman

Coulter LH 750)

• Data excluded if diagnosis of

SGA, PIH, sepsis.

First Platelet Count By Gestational Age

3 Days of Age or Less

0

100,000

200,000

300,000

400,000

500,000

Gestational Age

Pla

tele

t C

ou

nt

5th %ile Mean 95th %ile

5th %ile 87900 124050 97250 90400 103850102400107000112200105550101800108100126850110850123350115000125950130000124300121000110400

Mean 199400226470222020220810219370220150221410221250232260230930241390244320249280246800254040252870256810258920251280244370245990

95th %ile 331700342400316750337200352250337200328750352000339350355100363000370050367000373000378000382000384000374000364800382400

n 11 66 106 108 146 198 215 254 317 510 698 1090 1798 2456 3286 3910 5478 7600 4685 1143 71

22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

Feb 2009

Gestational Age (weeks) 5th %, mean, 95th %

Feb 2009

Platelet Count At Birth

http://www.nature.com/jp/journal/v28/n7/

First Platelet Count By Age in Days

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

0 7 14 21 28 35 42 49 56 63 70 77 84

Age in Days

Pla

tele

t C

ou

nt

Mean 5th %ile 95th %ile

Feb 2009

Feb 2009

Platelet Count, First 90 days After Birth



0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

0 7 14 21 28 35 42 49 56 63 70 77 84

Age in Days

Pla

tele

t C

ou

nt

Mean 5th %ile 95th %ile TPO SURGE

Feb 2009

Platelet Count, First 90 days After Birth


Mean Platelet Volume

Platelet size varies.

The MPV is an electronic

estimate of the average

size (volume) of platelets

in femtoliters (fL)

0

2

4

6

8

10

12

14

0 7 14 21 28 35 42 49 56 63 70 77 84

Age in Days

MP

V


Feb 2009


Sysmex® XE-Series

Automated

Hematology Analyzers

Since Changing to the Sysmex –

● Sometimes we don’t get a mean platelet

volume (MPV). Why?

● What is the immature platelet fraction (IPF)

reported on the Sysmex hematology analyzer?

● Platelet counts are identical between Sysmex

and Beckman Coulter (impedance).

● If the Sysmex fails to register a ‘reliable’

platelet count it switches from the impedance

(PLT-I mode) to an optical method (PLT-O mode)

that does not measure MPV.

● Immature platelet fraction (IPF) can be

measured on the Sysmex in the PLT-O mode.

Immature Platelet Fraction ●Forward scatter

estimates platelet SIZE

●Fluorescence intensity

estimates pl nucleic acid

concentration





concentration

●“Events” (dots) in the

IPF “gate” (green) are

“immature platelets”





concentration




● Green dots divided by

turquoise plus green

dots = IPF (%).





concentration




● Green dots divided by

turquoise plus green

dots = IPF (%).

● IPF reference range

for neonates, 2% to 5%

● Elevated IPF suggests

active production (large,

active) platelets

Outline

1) Reference ranges for platelets




●Most neonates with severe and

prolonged thrombocytopenia have

consumptive thrombocytopenia with a

cause that is apparent (e.g. sepsis/NEC).

●However some cases are congenital,

persistent, and puzzling.

Congenital Hyporegenerative

Thrombocytopenia

● Thrombocytopenia from birth, generally

<15,000/µL

● Not Alloimmune or TORCH or SEPSIS

● Normal response to platelet transfusion

● Reduced or absent megakaryocytes in

marrow, very high serum TPO level

Hyporegenerative

Congenital

Thrombocytopenia

Normal Size Platelets Small Platelets Large Platelets

Hyporegenerative

Congenital

Thrombocytopenia


MPV <5 fL MPV 8 to 12 fL MPV >15 fL

Hyporegenerative

Congenital

Thrombocytopenia



X-linked or

Wiskott Aldrich syndrome

Mutation in WAS at Xp11.23

Hyporegenerative

Congenital

Thrombocytopenia



Bernard Soulier [3q21.3, 17p13.2 or 22q11.21]

MYH9-related disorder[22q12.3]

von Willebrand disease type IIB VWF [12p13.31]

Congenital

Thrombocytopenia with

Normal Size Platelets

Are Specific Orthopedic Forearm

Anomalies Present?

YES or NO

Orthopedic anomalies YES Inability to pronate/supinate forearm

● ATRUS = Amegakaryocytic

Thrombocytopenia with

RadioUlnar Synostosis

A mutation in the HOXA11 gene @ 7p15.2

(haploinsufficient) - Autosomal Dominant

or de novo mutation)

Orthopedic anomalies YES

● TAR = Thrombocytopenia

and Absent Radii A microdeletion on 1q21.1 is

necessary (haploinsufficient).

This deletion plus a point

mutation on the allele

(RBM8A gene) –

Autosomal Recessive

Orthopedic anomalies NO

CAMT = Congenital Amegakaryocytic

Thrombocytopenia

A mutation in the TPO receptor

gene c-MPL @ 1 p34.2

Autosomal recessive,

compound heterozygotes

Severe Hyporegenerative Congenital

Thrombocytopenia and Normal Size Platelets

Forearm Defect?

Yes No

ATRUS TAR SGA or other anomalies?

No

CAMT

Yes

RUNX1 PTPN11 Jacobsen



Forearm Defect?

Yes No


No

CAMT

Yes

RUNX1 PTPN11

Symmetrical SGA, hyperteloric, developmental

delay, Microdeletion 11q23 (Genomic Microarray)

Jacobsen



Forearm Defect?

Yes No


No

CAMT

Yes

RUNX1 PTPN11

Symmetrical SGA, developmental delay,

Microdeletion 21q22.11 (Genomic Microarray)

Jacobsen

● Katzaki et al. Siena. Microdeletions of

21q22.11 Am J Med Genet 2010

● Christensen et al. Utah. Microdeletions of

21q22.11 J Perinatology 2012

● Click et al. Seattle. Microdeletions of

21q22.11 Am J Med Genet 2011

RUNX1 on Chromosome 21 Encodes a

Runt-Related Transcription Factor



Forearm Defect?

Yes No


No

CAMT

Yes

RUNX1 PTPN11

Noonan phenotype, SGA, developmental delay,

Mutation in PTPN11 12q24.13 [c.218 C>T]

Jacobsen



Forearm Defect?

Yes No


No

CAMT

Yes

RUNX1 PTPN11



Jacobson

Bambino Gesù Hospital, Rome



Forearm Defect?

Yes No


No

CAMT

Yes

RUNX1 PTPN11



Jacobson

Bambino Gesù Hospital, Rome

● Kratz C, Niemeyer CM et al. Germany. BLOOD 2005

● Nunes et al. Portugal. BMJ Case Reports 2012

● Christensen et al. USA. NEONATOLOGY 2013



Forearm Defect?

Yes No


No

CAMT

Yes

RUNX1 PTPN11

Mutation in TPO receptor (MPL) @ 1p34.2

Jacobsen

Outline





Platelet Transfusion in the 1950’s

Reduced mortality

rate of patients with

hemorrhage from

thrombocytopenia

due to acute

leukemia.

Platelet Transfusion in Todays NICU

2% = Treatment of thrombocytopenic bleeding.

98% = Prophylaxis. Hope to prevent bleeding

when platelets fall below arbitrary blood level.

Sola-Visner. Acquired thrombocytopenia. In

Neonatal Hematology, Eds. De Alarcon,

Werner, Christensen, 2012

RISKS vs. BENEFITS In non-bleeding,

thrombocytopenic neonates,

what are the RISKS of

prophylactic platelet

transfusions? What are the

BENEFITS?

Correlation: More NICU platelet

transfusions = Higher mortality rate Baer & Christensen 2009

Multiple platelet transfusions

to NICU patients are,

themselves, a risk factor for

adverse outcome.

Dec 2007


BENEFITS: Do prophylactic

platelet transfusions prevent

intraventricular hemorrhage?

1. Andrew - pl 50,000 vs. 150,000/µL. J

Pediatr 1993…No

2. Del Vecchio - pl in the range 100,000 -

150,000/µL do not increase bleeding

time J Perinatol 2008…No

3. Von Lindern - Platelet transfusion and

IVH. Comparison of a “liberal” vs.

“restrictive” guidelines. Arch Dis Child

2012…No

4. Sola (PAS 2012) - Relationship between

platelet count and IVH in VLBW

neonates?....No

Consider MORE than just the

platelet count.

Adequacy of platelet plug formation

depends on:

1) Platelet count

2) Platelet size

3) Platelet function

4) Platelet/endothelial interaction

PLATELET TRANSFUSION

Platelet plug formation may

be predicted better by the

PLATELET MASS than by

the platelet count.

Platelet count X MPV

= Platelet Mass

Is it more appropriate to base platelet

transfusion decisions on platelet mass

than on platelet count?

We speculated that doing so would:

1. Reduce the number of pl transfusions

2. Specifically reduce those pl

transfusion that are not helpful

3. Reduce costs

4. Preserve a valuable resource

Pilot Trial

2007

Guidelines

Transfuse if the:

Risk Group 1. (ECMO,

bleeding or pre- or

postoperative)

Platelets fall below

100,000/µL

Risk Group 2. (Not

bleeding and unstable)


50,000/µL

Risk Group 3. (Not

bleeding and stable)

Platelets below

20,000/µL

PROVO, UT OGDEN, UT

Pilot Trial

2007

Guidelines

Transfuse if the:

2008

Guidelines

Transfuse if the:


bleeding or pre- or

postoperative)


100,000/µL

Platelet mass falls

below 800 fL/nL

Risk Group 2. (Not



50,000/µL

Platelet mass falls

below 400 fL/nL

Risk Group 3. (Not


Platelets below

20,000/µL

Platelet mass falls

below 160 fL/nL

PROVO, UT OGDEN, UT

Pilot Trial

2007

Guidelines

Transfuse if the:

2008

Guidelines

Transfuse if the:


bleeding or pre- or

postoperative)


100,000/µL

Platelet mass falls

below 800 fL/nL

Risk Group 2. (Not



50,000/µL

Platelet mass falls

below 400 fL/nL

Risk Group 3. (Not


Platelets below

20,000/µL

Platelet mass falls

below 160 fL/nL

PROVO, UT OGDEN, UT

Platelet count X MPV

= Platelet Mass

“Mass” Guidelines Resulted in

Fewer Platelet Transfusions with

no Increase in Bleeding Problems

% receiving

one or more

pl trans

IVH all

grades

Pulmonary Gastrointestinal Cutaneous

2007

Platelet

Count

3.6% 5.0% 0.6% 2.0% 6.2%

2008

Platelet

Mass

1.9% 4.5% 0.7% 1.4% 5.3%

P value <0.002 0.36 0.52 0.27 0.02

2009

Previous

Guidelines

Transfuse if the:

Present

Guidelines

Transfuse if the:


bleeding or pre- or

postoperative)

Platelet count

falls below

100,000/µL

Platelet mass falls

below 800 fL/nL

Risk Group 2. (Not


Platelet count

falls below

50,000/µL

Platelet mass falls

below 400 fL/nL

Risk Group 3. (Not


Platelet count

falls below

20,000/µL

Platelet mass falls

below 160 fL/nL

Recommend Abandoning Platelet COUNT-

based Guidelines Adopting Platelet MASS-

based Guidelines

Outline





Romiplostim ● Analog of thrombopoietin

● Developed by Amgen under the trade name Nplate

● FDA approved 2008 for long-term treatment for chronic

ITP in adults who have not responded to other treatments.

● The wholesale cost of romiplostim if administered

weekly (adults) is about $55,000 per year.

● IV or sub Q use only

Eltrombopag

● Small molecule agonist of the Thrombopoietin receptor

● Discovered as a result of research collaboration

between GlaxoSmithKline and Ligand Pharmaceuticals.

●FDA approved in 2008 for adults with ITP refractory to

other treatments

●Oral preparation only

http://upload.wikimedia.org/wikipedia/commons/a/a7/Eltrombopag.svg

Those few had chronic, transfusion-dependent,

hyporegenerative thrombocytopenias or severe

liver disease (TPO is produced by hepatocytes).

Romiplostim and Eltrombopag

have been used

in very few neonates

PREDICTION: These medications will likely have a

limited value in the majority of cases of neonatal

thrombocytopenia, but will benefit neonatal patients with

certain uncommon varieties.

1) Not rapid-acting (10 days)

2) Not effective for most TPO receptor mutations (CAMT)

3) May elevate platelet count to safe range with certain

hyporegenerative thrombocytopenias (MYH9, RUNX1)

4) Likely to reduce pl transfusions for neonates with liver diseases

Recap

1)Reference ranges for platelet counts: gestational and post-natal age.

First Platelet Count By Gestational Age

3 Days of Age or Less

0

100,000

200,000

300,000

400,000

500,000

Gestational Age

Pla

tele

t C

ou

nt

5th %ile Mean 95th %ile

5th %ile 87900 124050 97250 90400 103850102400107000112200105550101800108100126850110850123350115000125950130000124300121000110400

Mean 199400226470222020220810219370220150221410221250232260230930241390244320249280246800254040252870256810258920251280244370245990

95th %ile 331700342400316750337200352250337200328750352000339350355100363000370050367000373000378000382000384000374000364800382400

n 11 66 106 108 146 198 215 254 317 510 698 1090 1798 2456 3286 3910 5478 7600 4685 1143 71

22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42


0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

0 7 14 21 28 35 42 49 56 63 70 77 84

Age in Days

Pla

tele

t C

ou

nt


Feb 2009


Recap 2) Advances in understanding congenital hyporegenerative thrombocytopenias

Recap


Platelet Mass 2009

Recap

4) Romiplostim and Eltrombopag

Evidence-based

neonatology hematology

= better outcomes for

NICU patients

Advances in the diagnosis and management of neonatal thrombocytopenia

Thanks for your kind attention!

"Ordem e Progresso" L’amour pour principe et l’ordre pour base; le

progrès pour but (Love as a principle and order as

the basis; progress as the goal)

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